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                迷失的字符串                </h1>
                <p>时间限制：10s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：512MB</p>			</div>
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                                <h3>题目描述</h3><p><div>有一棵n个节点的大树，上面每条边有一个小写字符。</div>
<div>对于任意两个不同的点u,v，我们可以在树上找到u出发到v终止的唯一的一条最短路径，并将沿途经过的边上的字符依次写下来，得到一个字符串。</div>
<div>对于一个字符串，如果存在这样一个点对(u,v)，使得它们路径上的字符串与其完全匹配，那么我们就称这个字符串属于这棵树。</div>
<div>现在有m个迷失的字符串，请你写一个程序帮助判断每一条字符串是否属于这棵树。</div>
<p></p></p><hr/><h3>输入格式</h3><p><div>第一行包含一个正整数n(2&lt;=n&lt;=30000)，表示树的点数。</div>
<div>接下来n-1行每行包含两个正整数a,b和一个小写字符c(1&lt;=a,b&lt;=n,a!=b)，表示a点到b点之间有一条无向的树边，上面写着字符c。</div>
<div>接下来一行包含一个正整数m(1&lt;=m&lt;=30000)，表示迷失的字符串的个数。</div>
<div>接下来m行，每行一个由小写字符组成的字符串，分别表示每个迷失的字符串。</div>
<div>输入数据保证所有迷之的字符串的长度之和不超过30000。</div>
<p></p></p><hr/><h3>输出格式</h3><p><div>包含m行，对于第i行，如果在树上可以找到第i个字符串，输出YES，否则输出NO。</div>
<p></p></p><hr/><h3>样例输入</h3><pre>4
1 2 b
1 4 a
2 3 c
9
bc
cb
b
c
d
aa
ab
abc
cba</pre><hr/><h3>样例输出</h3><pre>YES
YES
YES
YES
NO
NO
YES
YES
YES</pre><hr/><h3>提示</h3><p>没有写明提示</p><hr/><h3>题目来源</h3><p>By Claris</p>
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